1. Field of the Invention
The present invention relates to a printed wiring board and a wireless communication system, and in particular, relates to a printed wiring board and a wireless communication system, preferably for use in an RFID (Radio Frequency Identification) system.
2. Description of the Related Art
In recent years, as an information management system for articles, there has been put into practical use an RFID system where communication is established between a reader/writer generating an induction magnetic field and an RFID tag attached to an article on the basis of a non-contact method utilizing an electromagnetic field and predetermined information is transmitted. This RFID tag includes a wireless IC chip storing therein the predetermined information and processing a predetermined wireless signal and an antenna (radiator) performing transmission and reception of a high-frequency signal.
In some cases, the RFID system is used for information management for printed wiring boards embedded in various kinds of electronic devices. For example, in International Publication No. WO 2009/011144 or International Publication No. WO 2009/011154, an RFID tag is disclosed that utilizes, as an antenna, the ground electrode of a printed wiring board. In this RFID tag, a loop-shaped electrode for matching impedance is provided between a wireless IC chip and a ground electrode. Therefore, it is possible to realize an RFID tag having a simple configuration and a small signal loss.
Incidentally, while the RFID tag described in International Publication No. WO 2009/011144 or International Publication No. WO 2009/011154 has a simple configuration, the ground electrode functioning as an antenna becomes a barrier to signal transmission and reception, and the radiation characteristic of a high-frequency signal is not necessarily good.